﻿COCCOSTEHLE. 309 



18C0. Heterostius eurynotus, E. von Eichwald, Leth. Rossica, vol. i. 

 p. 1524. 



Type. Fragment of dermal armour. 



The type species, of very large size, known only from separately- 

 discovered bones. Forwardly-directed process of anterior dorso- 

 lateral more than twice as long as the remainder of the bone. 

 Ornamentation sparse. 



Form. <$f Log. Lower Devonian : Livonia. 



The following are plaster casts of the original bones from Livonia 

 in the University of Dorpat, described by Asmuss, and were pre- 

 sented by Sir Roderick I. Murchison, K.C.B., about 1846 : — 



15142 j. Imperfect median dorsal plate, shown from the inner 

 aspect and the posterior margin placed uppermost by 

 Agassiz (op. cit. pi. xxxii. fig. 13) ; the type specimen of 

 H. huechii, Asmuss (op. cit. p. 28, no. 1), described as 

 " scutum dorsale anterius." 



15142 k. Fragment of middle portion of a similar plate (Agassiz, 

 pi. xxxii. fig. 8); the type specimen of H. gracilior, 

 Asmuss (p. 28, no. 2). 



15142 1. Anterior portion of inner keel of median dorsal shield ; 

 the type specimen of H. conveccus, Asmuss (p. 28, no. 3). 



15142 m. Fragment of median dorsal shield (Agassiz, pi. xxxii. 

 figs. 11, 12); the type specimen of H. eurynotus, Asmuss 

 (p. 28, no. 4). 



15142 n. Imperfect right anterior dorso-lateral (Agassiz, pi. xxxii. 

 fig. 19); described by Asmuss (p. 30, no. 19) as " admi- 

 niculum laterale " of H. eurynotus. 



15142 0. Similar bone, less imperfect, but scarcely more than half 

 as large as the latter (Agassiz, pi. xxxii. fig. 18, Pander, 

 pi. viii. fig. 1") ; described by Asmuss (p. 30, no. 18) as 

 H. conveocus. 



15142 p. Fragment of process of similar bone; assigned to H. in- 

 gens by Asmuss (p. 30, no. 20). 



15142 q.. Expanded portion of a similar bone, left side : the type 

 specimen of H. secundarius, Asmuss (p. 30, no. 22). 



15142 r. Similar specimen, showing overlapping fragments poste- 

 riorly ; the type specimen of H. initiate, Asmuss (p. 31, 

 no. 25). 



